1. Field of the Invention
The present invention relates to a gold layer-laminated fabric and method for fabricating the same, and more particularly, to a fabric fabricated by plating a copper layer and a gold or platinum layer on a fibrous fabric substrate continuously, thereby permitting the fabric to have superior thermal conductivity, electrical conductivity, moth repellency, and antibacterial potency. Moreover, this present invention relates to a method for fabricating a fabric by plating a copper layer and a gold or a platinum layer on a fibrous fabric substrate.
2. Description of the Related Art
Conductive fabric has been originally developed by the National Aeronautic and Space Administration (NASA) for the purpose of a prevention of erroneous operations of aerospace equipment allowing no error. Currently, such conductive fabrics are applied to all industrial fields in order to provide a good protection for the human body and to avoid a loss resulting from erroneous operations of industrial appliance.
An example of a conventional conductive fabric is a fabric having an electromagnetic shield layer formed by spraying or coating a mixture of conductive carbon, copper, manganese, and adhesive onto a fabric substrate. However, such a fabric has drawbacks in that the process capability, venting capability, and flexibility thereof, which are the intrinsic characteristics of fabrics, are degraded because the electromagnetic shield layer is formed using a method of directly spraying or coating the mixture on the fabric substrate, even though it provides a shielding effect against electromagnetic waves.
Fabric products have also been developed, in which an outermost layer thereof externally exposed is made of nickel, copper, carbon, or silver. In the case using nickel, an allergic reaction may occur when the outermost layer is in prolonged contact with the skin. In the case, there is also a problem of corrosion or decoloration. Furthermore, this product exhibits degraded thermal and electrical conductivities. In fabric products using copper or silver, there is a problem of corrosion or decoloration. In the case using carbon, there is a problem in that very degraded thermal and electrical conductivities are exhibited.
Generally, garments made of fabrics with metal coatings have been developed only to provide a specific function such as an electromagnetic shield function, without taking into consideration the health of wearers or the aesthetic appeal of those garments. Furthermore, the recent advance in radio communications results in a demand for functional garments having functions associated with radio communications. However, there is no practical product associated with such functional garments.
Therefore, an object of the invention is to provide a fabric exhibiting superior venting capability, moth repellency, antibacterial potency, thermal conductivity, and electrical conductivity.
Another object of the invention is to provide a fabric exhibiting no decoloration and while being harmless to the human body and exhibiting metallic brilliance.
Another object of the invention is to provide a fabric capable of avoiding an allergic reaction, harmful to the body of the wearer, caused by an inner layer thereof exposed due to the peel-off of an outermost layer thereof.
Another object of the invention is to provide a method for fabricating a fabric capable of accomplishing the above mentioned objects.
In accordance with one aspect, the present invention provides a conductive fabric comprising: a fibrous fabric substrate having the form of a woven, non-woven or mesh sheet; a first layer of copper formed on the fibrous fabric substrate by an electroless plating process; a second layer gold or platinum formed, as an externally exposed layer, on the first layer continuously. The conductive fabric may further comprise a third layer made of nickel and interposed between the fibrous fabric substrate and the first layer, the third layer being formed by an electroless plating process.
The nickel and copper layers may be formed using an electroless plating process whereas the gold or platinum layer may be formed using either an electrolytic plating process or an electroless plating process. Preferably, the nickel layer has a thickness of 0.1 to 0.2 cm, the copper layer has a thickness of 0.3 to 0.7 cm, and the gold or platinum layer has a thickness of 0.05 to 0.2 xcexcm.
The fibrous fabric substrate may be made of a fiber selected from the group consisting of polyester fibers, acrylic fibers, and polyamide fibers. The fibrous fabric substrate is made of a fiber having a form of a mono-filament or a multi-filament.
In accordance with another aspect, the present invention provides a method for fabricating a conductive fabric, the method comprises the step of: preparing a fibrous fabric substrate fabricated using a polyester-based fiber made of a condensation polymer of a terephthalic acid and an isopropyl alcohol; applying 80 to 90 g/l of a sodium hydroxide to the fibrous fabric substrate, and conducting an etching process for the fibrous fabric substrate at a temperature of 80xc2x0 C. partially to remove the terephthalic acid; applying a hydrochloric acid to the fibrous fabric substrate to neutralize the sodium hydroxide, and then applying a complex salt consisting of a palladium chloride (PdCl2), a tin chloride (SnCl2), and a hydrochloric acid (HCl) to the fibrous fabric substrate to substitute the complex salt for locations from which the terephthalic acid is removed; applying a sulphuric acid to the fibrous fabric substrate at a temperature of about 40 to 60xc2x0 C. to metallize a palladium existing in an ionized state in the fibrous fabric substrate; washing the fibrous fabric substrate, and applying a cuprous chloride, a formalin, a Rochelle salt, a citrate, an ethylene diamine tetraacetic acid (EDTA), and a sodium hydroxide to the fibrous fabric substrate to form a copper layer on the fibrous fabric substrate; and applying a potassium gold cyanids, an EDTA, a citrate, and an aqueous ammonia to the fibrous fabric substrate to form a gold layer on the copper layer.
Preferably, the copper layer is formed to have a thickness of 0.3 to 0.7 xcexcm in accordance with an electroless plating process conducted, using the cuprous chloride in a concentration of about 10 to 30 g/l, the formalin in a concentration of about 10 to 30 g/l, the Rochelle salt in a concentration of about 5 to 10/l, the citrate in a concentration of about 5 to 10 g/l, the EDTA in a concentration of about 20 to 30 g/l, and the sodium hydroxide in a concentration of about 5 to 10 g/l, at a temperature of about 40 to 50xc2x0 C. and a ph of 12.0 to 13.0. Preferably, the gold layer is formed to have a thickness of 0.05 to 0.2 xcexcm in accordance with an electroless plating process conducted, using the potassium gold cyanide in a concentration of about 0.5 to 2 g/l, the EDTA in a concentration of about 15 to 25 g/l, the citrate in a concentration of about 15 to 25 g/l, and the aqueous ammonia in a concentration of about 10 to 30 ml/l.
Alternatively, the formation of the gold layer it carried out in accordance with an electrolytic plating process conducted using a potassium gold cyanide in a concentration of about 60 to 80 g/l, a cobalt in a concentration of about 0.7 to 0.9 g/l, and a conductive salt in a desired concentration, at a temperature of 20 to 50xc2x0 C. and a pH of 3.8 to 4.3.
In order to provide an increased bonding force of the copper layer to the fibrous fabric substrate, nickel exhibiting an electrical conductivity similar to that of activated palladium ions may by plated on the fibrous fabric substrate. The nickel layer may be formed to have a thickness of 0.1 to 0.2 xcexcm in accordance with an electroless plating process using a nickel sulfate, a sodium hypophospite, and a citrate. Preferably, the formation of the nickel layer is carried out in accordance with an electroless plating process conducted, using the nickel sulfate in a concentration of about 10 to 20 g/l, the sodium hypophospite in a concentration of about 7.5 to 15 g/l, and the citrate in a concentration of about 15 to 30 g/l, at a temperature of about 0.30 to 40xc2x0 C.